NASHVILLE, Tenn. (AP) — Former Vice President Al Gore is not attending the Democratic National Convention in Philadelphia this week.

Spokeswoman Betsy McManus told The Tennessean newspaper that Gore has “obligations in Tennessee,” but she did not elaborate.

Gore is one of eight Tennessee superdelegates, but he has not pledged his support to presumptive nominee Hillary Clinton.

Gore was a Tennessee U.S. senator before joining Bill Clinton’s presidential ticket in 1992. Gore lost the 2000 presidential race to Republican George W. Bush.

Since then Gore has become increasingly less active in electoral politics and more active in environmental causes, sharing the Nobel Peace Prize in 2007 for that effort.

Gore spoke on behalf of Democratic nominees John Kerry in 2004 and Barack Obama in 2008, but he did not attend the 2012 convention.

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